Black pepper is the unripened fruit of piper nigrum dried in the sun; white pepper is the same fully ripened (in Kerala the seeds of Moringa oleifera are used for white pepper). Both varieties of P. nigrum are pungent. They decrease kapha and vata and increase pitta only slightly, because their drying quality counteracts pitta's only quality. The unripened, un-dried green 'version of this spice is heavy, has a sweet post-digestive effect, is not too hot and is pickled in western India for use as a condiment.

References: Ayurveda Life Health and Longevity by Robert E. Svoboda - Penguin Books.